Fractal energy gaps and topological invariants in hBN/graphene/hBN double moir? systems
Fractal energy gaps and topological invariants in hBN/graphene/hBN double moir? systems
复制标题
六方氮化硼/石墨烯/六方氮化硼双莫尔条纹中的分形能隙和拓扑不变量？
DOI：
10.1103/physrevb.104.035306
复制
发表时间：
2021
影响因子：
3.7
通讯作者：
Koshino Mikito
中科院分区：
文献类型：
--
作者：
Oka Hiroki;Koshino Mikito
我们计算了六方氮化硼（hBN）夹持石墨烯准周期双莫尔系统的电子结构，并确定了能隙的特征整数。我们发现，电子光谱包含了一些minigaps，他们表现出递归分形结构类似于霍夫施塔特蝴蝶时，绘制对扭转角。每个能隙都可以用一组整数来表征，这些整数与动量空间中的面积相关联。相应的区域被几何解释为准布里渊区，它是由多个复合周期的布拉格平面包围的多边形，并且可以由弱势极限中的平波投影唯一地指定。
We calculate the electronic structure in quasiperiodic double moiré systems of graphene sandwiched by hexagonal boron nitride (hBN) and identify the characteristic integers of energy gaps. We find that the electronic spectrum contains a number of minigaps, and they exhibit a recursive fractal structure similar to the Hofstadter butterfly when plotted against the twist angle. Each of the energy gaps can be characterized by a set of integers, which are associated with an area in momentum space. The corresponding area is geometrically interpreted as a quasi-Brillouin zone, which is a polygon enclosed by multiple Bragg planes of the composite periods and can be uniquely specified by the plain wave projection in the weak-potential limit.